Heating, Air Conditioning, Fridge, HVAC/BLOWER MOTOR RPM

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Question
JIM,
I HAVE A 1962 INTERNATIONAL FORCED AIR FURNACE (FLOOR REGISTERS),IN A MOBILE HOME, WITH A LATER ADDED SEARS A/C CONDENSING UNIT. THE PREVIOUS OWNER REPLACED THE BLOWER MOTOR WITH A 3 SPEED MOTOR, WIRED TO THE HIGHEST RPM, WHICH DOESN'T SEEM RIGHT. IS THERE A STANDARD RPM THAT THE BLOWER CAGE SHOULD RUN AT? I CAN'T FIND A RPM LISTED ON ANY PLACARD.

THANKS,

KELLY

Answer
Kelly,
If you look on the motors rating plate  itself it should tell what RPM the motor is running at.
The CFM is what you should be concerned about?
The motor drives the blower wheel which produces the CFM.
If the motor is different then the original motor the furnace came with the speck sheet that should be pasted on the inside of the blower compartment may not help?
The furnace blower needs to produce 400 CFM per ton of cooling.
There should also be a blower relay on the furnace that changes the RPM & CFM for heating or cooling depending on what the thermostat is set at?

Heating, Air Conditioning, Fridge, HVAC

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Jim Barnhart

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Fifty + years conditioning the air.

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Answer questions about , residential and commercial. Answer questions about sheet metal fabrication. Fifty years plus experience. No answers for oil equipment, No answers for kitchen appliances, No answers for laundry appliances, I don't specialize in one particular area of the HVAC area, I'm more of a General Practitioner, Limited in refrigeration/

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Hands on since 1950

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